/* -------------------------------------------------------------------------
 *
 * contrib/sepgsql/proc.c
 *
 * Routines corresponding to procedure objects
 *
 * Copyright (c) 2010-2017, PostgreSQL Global Development Group
 *
 * -------------------------------------------------------------------------
 */
#include "postgres.h"

#include "access/genam.h"
#include "access/heapam.h"
#include "access/htup_details.h"
#include "access/sysattr.h"
#include "catalog/dependency.h"
#include "catalog/indexing.h"
#include "catalog/pg_namespace.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_type.h"
#include "commands/seclabel.h"
#include "lib/stringinfo.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"
#include "utils/tqual.h"

#include "sepgsql.h"

/*
 * sepgsql_proc_post_create
 *
 * This routine assigns a default security label on a newly defined
 * procedure.
 */
void
sepgsql_proc_post_create(Oid functionId)
{
    Relation    rel;
    ScanKeyData skey;
    SysScanDesc sscan;
    HeapTuple    tuple;
    char       *nsp_name;
    char       *scontext;
    char       *tcontext;
    char       *ncontext;
    uint32        required;
    int            i;
    StringInfoData audit_name;
    ObjectAddress object;
    Form_pg_proc proForm;

    /*
     * Fetch namespace of the new procedure. Because pg_proc entry is not
     * visible right now, we need to scan the catalog using SnapshotSelf.
     */
    rel = heap_open(ProcedureRelationId, AccessShareLock);

    ScanKeyInit(&skey,
                ObjectIdAttributeNumber,
                BTEqualStrategyNumber, F_OIDEQ,
                ObjectIdGetDatum(functionId));

    sscan = systable_beginscan(rel, ProcedureOidIndexId, true,
                               SnapshotSelf, 1, &skey);

    tuple = systable_getnext(sscan);
    if (!HeapTupleIsValid(tuple))
        elog(ERROR, "could not find tuple for function %u", functionId);

    proForm = (Form_pg_proc) GETSTRUCT(tuple);

    /*
     * check db_schema:{add_name} permission of the namespace
     */
    object.classId = NamespaceRelationId;
    object.objectId = proForm->pronamespace;
    object.objectSubId = 0;
    sepgsql_avc_check_perms(&object,
                            SEPG_CLASS_DB_SCHEMA,
                            SEPG_DB_SCHEMA__ADD_NAME,
                            getObjectIdentity(&object),
                            true);

    /*
     * XXX - db_language:{implement} also should be checked here
     */


    /*
     * Compute a default security label when we create a new procedure object
     * under the specified namespace.
     */
    scontext = sepgsql_get_client_label();
    tcontext = sepgsql_get_label(NamespaceRelationId,
                                 proForm->pronamespace, 0);
    ncontext = sepgsql_compute_create(scontext, tcontext,
                                      SEPG_CLASS_DB_PROCEDURE,
                                      NameStr(proForm->proname));

    /*
     * check db_procedure:{create (install)} permission
     */
    initStringInfo(&audit_name);
    nsp_name = get_namespace_name(proForm->pronamespace);
    appendStringInfo(&audit_name, "%s(",
                     quote_qualified_identifier(nsp_name, NameStr(proForm->proname)));
    for (i = 0; i < proForm->pronargs; i++)
    {
        if (i > 0)
            appendStringInfoChar(&audit_name, ',');

        object.classId = TypeRelationId;
        object.objectId = proForm->proargtypes.values[i];
        object.objectSubId = 0;
        appendStringInfoString(&audit_name, getObjectIdentity(&object));
    }
    appendStringInfoChar(&audit_name, ')');

    required = SEPG_DB_PROCEDURE__CREATE;
    if (proForm->proleakproof)
        required |= SEPG_DB_PROCEDURE__INSTALL;

    sepgsql_avc_check_perms_label(ncontext,
                                  SEPG_CLASS_DB_PROCEDURE,
                                  required,
                                  audit_name.data,
                                  true);

    /*
     * Assign the default security label on a new procedure
     */
    object.classId = ProcedureRelationId;
    object.objectId = functionId;
    object.objectSubId = 0;
    SetSecurityLabel(&object, SEPGSQL_LABEL_TAG, ncontext);

    /*
     * Cleanup
     */
    systable_endscan(sscan);
    heap_close(rel, AccessShareLock);

    pfree(audit_name.data);
    pfree(tcontext);
    pfree(ncontext);
}

/*
 * sepgsql_proc_drop
 *
 * It checks privileges to drop the supplied function.
 */
void
sepgsql_proc_drop(Oid functionId)
{
    ObjectAddress object;
    char       *audit_name;

    /*
     * check db_schema:{remove_name} permission
     */
    object.classId = NamespaceRelationId;
    object.objectId = get_func_namespace(functionId);
    object.objectSubId = 0;
    audit_name = getObjectIdentity(&object);

    sepgsql_avc_check_perms(&object,
                            SEPG_CLASS_DB_SCHEMA,
                            SEPG_DB_SCHEMA__REMOVE_NAME,
                            audit_name,
                            true);
    pfree(audit_name);

    /*
     * check db_procedure:{drop} permission
     */
    object.classId = ProcedureRelationId;
    object.objectId = functionId;
    object.objectSubId = 0;
    audit_name = getObjectIdentity(&object);

    sepgsql_avc_check_perms(&object,
                            SEPG_CLASS_DB_PROCEDURE,
                            SEPG_DB_PROCEDURE__DROP,
                            audit_name,
                            true);
    pfree(audit_name);
}

/*
 * sepgsql_proc_relabel
 *
 * It checks privileges to relabel the supplied function
 * by the `seclabel'.
 */
void
sepgsql_proc_relabel(Oid functionId, const char *seclabel)
{
    ObjectAddress object;
    char       *audit_name;

    object.classId = ProcedureRelationId;
    object.objectId = functionId;
    object.objectSubId = 0;
    audit_name = getObjectIdentity(&object);

    /*
     * check db_procedure:{setattr relabelfrom} permission
     */
    sepgsql_avc_check_perms(&object,
                            SEPG_CLASS_DB_PROCEDURE,
                            SEPG_DB_PROCEDURE__SETATTR |
                            SEPG_DB_PROCEDURE__RELABELFROM,
                            audit_name,
                            true);

    /*
     * check db_procedure:{relabelto} permission
     */
    sepgsql_avc_check_perms_label(seclabel,
                                  SEPG_CLASS_DB_PROCEDURE,
                                  SEPG_DB_PROCEDURE__RELABELTO,
                                  audit_name,
                                  true);
    pfree(audit_name);
}

/*
 * sepgsql_proc_setattr
 *
 * It checks privileges to alter the supplied function.
 */
void
sepgsql_proc_setattr(Oid functionId)
{
    Relation    rel;
    ScanKeyData skey;
    SysScanDesc sscan;
    HeapTuple    oldtup;
    HeapTuple    newtup;
    Form_pg_proc oldform;
    Form_pg_proc newform;
    uint32        required;
    ObjectAddress object;
    char       *audit_name;

    /*
     * Fetch newer catalog
     */
    rel = heap_open(ProcedureRelationId, AccessShareLock);

    ScanKeyInit(&skey,
                ObjectIdAttributeNumber,
                BTEqualStrategyNumber, F_OIDEQ,
                ObjectIdGetDatum(functionId));

    sscan = systable_beginscan(rel, ProcedureOidIndexId, true,
                               SnapshotSelf, 1, &skey);
    newtup = systable_getnext(sscan);
    if (!HeapTupleIsValid(newtup))
        elog(ERROR, "could not find tuple for function %u", functionId);
    newform = (Form_pg_proc) GETSTRUCT(newtup);

    /*
     * Fetch older catalog
     */
    oldtup = SearchSysCache1(PROCOID, ObjectIdGetDatum(functionId));
    if (!HeapTupleIsValid(oldtup))
        elog(ERROR, "cache lookup failed for function %u", functionId);
    oldform = (Form_pg_proc) GETSTRUCT(oldtup);

    /*
     * Does this ALTER command takes operation to namespace?
     */
    if (newform->pronamespace != oldform->pronamespace)
    {
        sepgsql_schema_remove_name(oldform->pronamespace);
        sepgsql_schema_add_name(oldform->pronamespace);
    }
    if (strcmp(NameStr(newform->proname), NameStr(oldform->proname)) != 0)
        sepgsql_schema_rename(oldform->pronamespace);

    /*
     * check db_procedure:{setattr (install)} permission
     */
    required = SEPG_DB_PROCEDURE__SETATTR;
    if (!oldform->proleakproof && newform->proleakproof)
        required |= SEPG_DB_PROCEDURE__INSTALL;

    object.classId = ProcedureRelationId;
    object.objectId = functionId;
    object.objectSubId = 0;
    audit_name = getObjectIdentity(&object);

    sepgsql_avc_check_perms(&object,
                            SEPG_CLASS_DB_PROCEDURE,
                            required,
                            audit_name,
                            true);
    /* cleanups */
    pfree(audit_name);

    ReleaseSysCache(oldtup);
    systable_endscan(sscan);
    heap_close(rel, AccessShareLock);
}

/*
 * sepgsql_proc_execute
 *
 * It checks privileges to execute the supplied function
 */
void
sepgsql_proc_execute(Oid functionId)
{
    ObjectAddress object;
    char       *audit_name;

    /*
     * check db_procedure:{execute} permission
     */
    object.classId = ProcedureRelationId;
    object.objectId = functionId;
    object.objectSubId = 0;
    audit_name = getObjectIdentity(&object);
    sepgsql_avc_check_perms(&object,
                            SEPG_CLASS_DB_PROCEDURE,
                            SEPG_DB_PROCEDURE__EXECUTE,
                            audit_name,
                            true);
    pfree(audit_name);
}
